Cat5 camera flash extension

Network engineer [Mario Giambanco] recently purchased a cable to move his flash off camera. Unfortunately, it ended up way too short for his purposes. Instead of purchasing a slightly longer proprietary cable, he decided to employ what he had around him: a lot of cat5e cable and ethernet jacks. He cut the cable close to the center in case things didn’t work out and he’d need to repair it. His post on building the custom ethernet flash extension cable goes into heavy detail to make sure you get it right the first time. He’s tested it using both five and 50 foot pieces of cable with no apparent lag.

Post navigation

11 thoughts on “Cat5 camera flash extension”

I wouldn’t wanna be holding the cat5 cable when the flash goes off. That stuff doesn’t have too much insulation, and knowing from experience of getting zapped by a disposable camera flash (to make a rail gun) it isn’t nice.

It’s just a low voltage signal that goes through the wire. The flash has batteries in, and all the camera does is short the wires to trigger the flash. I’m basing this on the scientific data of having fired a flash while touching the terminals.

I don’t see how this could ever have an effect on latency. The speed of light is pretty damn fast however long your cable is.

Well, considering the hotshoe connector is used for much more than flash modules these days and said alternative devices would probably fry with the stepped up voltage/amperage needed to fire off a flash, I’d say it’s simply a low voltage trigger going through the hotshoe so it won’t cause much harm to the cable or the user.

The voltage depends on the flash. I have several, digital safe flashes tend to be under 6v, while older ones vary. One I got from a small East German camera, went up to 450 volts between the ground and trigger pin. The flashes fire when the trigger pin is connected to the ground, which in old cameras and flashes may not have actually been grounded to anything at all. So user beware.

Most flashes do not use the connection to send the voltage from the cap to the xenon tube firing system. Most. Once you see a flash with 400+ volts across that gap, you have to wonder though.

For older cameras and flashes, this would have been too many cables to have bothered with. You just need the connection. Now, though, the flashes use serial signals to talk to the camera,. And the camera companies like to charge a lot for even short cables. This looks like a nice project for anyone without real wireless flashes or ebay wizards. But only with newer flashes and known gear.

Sheesh – ignorance is a scary thing.
Old flashes will pass hundreds of volts through this cable (and fry your new digital camera). New flashes will pass ~6v through it. This is a TTL cable so it’ll be using a reasonably new flash, I’m expecting about 6v.http://www.botzilla.com/photo/strobeVolts.html
Botzilla shows which flashes are ‘safe’ and which are not.